EVALUATION OF PHYSICOCHEMICAL AND MICROBIOLOGICAL QUALITY OF DRINKING WATER IN THE DISTRIBUTION SYSTEM OF DHARAN, NEPAL

Abstract

Water is an essential part of the ecosystem that supports life on the earth since it contains essential elements for human health. Studies of the water's constituents are essential to obtaining a precise picture of the water quality. Hence, 31 samples were taken from the drinking water distribution system of Dharan in 2022 for evaluating the physicochemical and microbiological quality of drinking water being distributed across the sub-metropolitan city. Though public knowledge and adequate management of watershed and reservoir premises were insufficient, the physicochemical characteristics were determined to be within the World Health Organization (WHO) and National Drinking Water Quality Standards (NDWQS) for drinking water with temperature ranging from 23.6°C to 25.6°C, pH 7.7 to 8.5, conductivity 38.2 to 38.7µmho/cm, DO 49.54 to 58.39 mg/l, BOD 2.61 to 5.22 mg/l, chloride 29.82 to 34.08 mg/l, nitrite 10 ppm and ammonia <0.5 ppm. However, the coliform bacteria levels were significant, with the highest TCC being 137 cfu/100ml, highest FCC being 85 cfu/100ml and highest TPC being TMTC. The water was found to be unsafe to drink without intensive disinfection treatments. It may be necessary to carry out treatment procedures like chlorination as advised by WHO as soon as possible while also taking in account the proper application of filtration techniques for distributing safe drinking water to the residents of Dharan.